on the 12th floor of chicago's merchandise mart, the people behind 185 digital- and technology-enabled startups have plugged in their laptops and are sharing stories of what works and what doesn't. a wall- sized chalkboard lists workshops in this collaborative workspace called "1871," the year chicago had to begin rebuilding itself from the great fire. "in this very large city, there's a density of entrepreneurs here where there's always something going on." it's the kind of environment that incubates what might be the next groupon or grubhub. this week, scott case, one of founders of priceline, hosted a forum on what it takes to launch a startup these days. "when you look at startups, try to network for captial for talent and for customers." one of the attendees, jere mcallister, who created a music media magazine for the ipad called "groovebug," just launched an app with iconic jazz label blue note. "we've partnered with other tech companies and they helped open doors for blue note." mcallister is one of more than a hundred entrepreneurs who see america's future in its startups, not